DI-19
Rear Differential (T-type)
DIFFERENTIALS
4. Rear Differential (T-type)
A: REMOVAL
1) Shift the select lever or gear shift lever to neutral.
2) Disconnect the ground cable from battery.
3) Release the parking brake.
4) Loosen the wheel nuts.
5) Lift up the vehicle.
6) Remove the rear wheels.
7) Disconnect the oil temperature sensor connec-
tor. (H5)
8) Drain differential gear oil. <Ref. to DI-16, RE-
PLACEMENT, Differential Gear Oil.>
9) Remove the rear exhaust pipe.
Except for STI model
<Ref. to EX(w/o STI)-50, REMOVAL, Rear Exhaust
Pipe.>
STI model
<Ref. to EX(STI)-12, REMOVAL, Rear Exhaust
Pipe.>
10) Remove the center exhaust cover.
11) Remove the propeller shaft. <Ref. to DS-12,
REMOVAL, Propeller Shaft.>
12) Loosen the self-lock nuts which hold the rear
differential to the rear sub frame assembly.
13) Remove the DOJ of rear drive shaft from rear
differential using ST.
NOTE:
When removing the DOJ from the rear differential,
fit the ST to the bolts as shown in the figure so as
not to damage the side retainer.
ST 28099PA100 DRIVE SHAFT REMOVER
14) Set the rear differential to transmission jack.
(A) Oil temperature sensor connector
DI-00991
(A)
DI-00972
(A) Bolt
DI-00996
DI-00270
(A)
ST
DI-00730
15WRX_STI_US_EN.book 19 ペー   
DI-20
Rear Differential (T-type)
DIFFERENTIALS
15) Remove the rear differential front member.
16) Remove the self-lock nuts which hold the rear
differential to the rear sub frame assembly.
17) Pull out the rear differential stud bolt from rear
differential mount bushing.
NOTE:
When removing the stud bolt from the rear differen-
tial mount bushing, carefully adjust the angle and
location of transmission jack and jack stand, if nec-
essary.
18) Lower the transmission jack.
19) Pull out the rear drive shaft from the rear differ-
ential.
NOTE:
If it is difficult to pull out the rear drive shaft from the
rear differential, remove it using a ST.
ST 28099PA100 DRIVE SHAFT REMOVER
20) Lower the transmission jack.
21) Secure the rear drive shaft to rear lateral link
using wire.
22) Remove the rear differential member plate from
rear differential.
DI-00731
DI-00996
DI-00733
(A) Rear differential member plate
DI-00974
DI-00734
DI-00359
(A)
15WRX_STI_US_EN.book 20 ペー   
DI-21
Rear Differential (T-type)
DIFFERENTIALS
B: INSTALLATION
1) Attach the rear differential member plate to the
rear differential.
2) Set the rear differential to transmission jack.
3) Set the ST to the rear differential.
ST 28099PA090 OIL SEAL PROTECTOR
4) Insert the rear drive shaft until the spline portion
of the rear drive shaft exceeds the side oil seal.
5) Remove ST from rear differential.
6) Push the rear differential from side to side to in-
sert the DOJ into rear differential completely.
7) Adjust the transmission jack, if necessary, and
insert the rear differential stud bolt into the rear dif-
ferential mount bushing properly.
8) After inserting the rear differential stud bolt into
the rear differential mount bushing, lift up the trans-
mission jack and align the rear differential to its at-
tachment position.
(A) Rear differential member plate
DI-00359
(A)
DI-00279
ST
DI-00280
DI-00735
DI-00733
DI-00736
15WRX_STI_US_EN.book 21 ペー   
DI-22
Rear Differential (T-type)
DIFFERENTIALS
9) Tighten a new self-locking nut temporarily to the
rear differential stud bolt.
10) Install the rear differential front member, and
temporarily attach and tighten a new self-locking
nut.
11) Remove the transmission jack.
12) Tighten the self-locking nut.
Tightening torque:
T1: 50 N·m (5.1 kgf-m, 36.9 ft-lb)
T2: 110 N·m (11.2 kgf-m, 81.1 ft-lb)
13) Tighten the self-locking nut.
Tightening torque:
70 N·m (7.1 kgf-m, 51.6 ft-lb)
14) Install the propeller shaft. <Ref. to DS-14, IN-
STALLATION, Propeller Shaft.>
15) Install the center exhaust cover.
Tightening torque:
18 N·m (1.8 kgf-m, 13.3 ft-lb)
16) Install the rear exhaust pipe.
Except for STI model
<Ref. to EX(w/o STI)-51, INSTALLATION, Rear
Exhaust Pipe.>
STI model
<Ref. to EX(STI)-12, INSTALLATION, Rear Ex-
haust Pipe.>
17) Fill differential gear oil. <Ref. to DI-16, RE-
PLACEMENT, Differential Gear Oil.>
18) Installing procedure hereafter is in the reverse
order of removal.
DI-00996
DI-00981
DI-00737
T2
T1
DI-00996
DI-00972
15WRX_STI_US_EN.book 22 ペー   
DI-23
Rear Differential (T-type)
DIFFERENTIALS
C: DISASSEMBLY
1. T-TYPE (B1, B2)
To detect the real cause of trouble, inspect the fol-
lowing items before disassembling.
Tooth contact and backlash between hypoid
driven gear and drive pinion
Hypoid driven gear runout on its back surface
Total preload of drive pinion
1) Set the ST on vise and install the differential as-
sembly to ST.
ST 398217700 ATTACHMENT SET
2) Remove the drain plug and filler plug.
3) Remove the air breather cap.
NOTE:
Do not attempt to remove the air breather cap
unless necessary.
Whenever the air breather cap is removed, re-
place it with a new part.
4) Remove the bolts, and then remove the rear
cover.
5) Remove the side retainer attachment bolts, set
the ST to differential case, and extract the side re-
tainers RH and LH with a puller.
NOTE:
Side retainer shim of each side should be kept
together with its mating retainer.
Keep the side retainers separate by attaching
tags or in similar ways to make it possible to identify
RH and LH sides during reassembly.
ST 398457700 ATTACHMENT
6) Pull out the differential case assembly from the
differential carrier.
NOTE:
Be careful not to hit the teeth of hypoid driven gear
against the differential carrier.
7) Remove the oil seal and O-ring from the side re-
tainer.
8) When replacing the side bearing, remove the
bearing race from the side retainer using ST.
ST 398527700 PULLER ASSY
(A) Air breather cap
(B) Rear cover
DI-00061
ST
(A)
(B)
DI-00672
DI-00064
ST
DI-00065
DI-00066
ST
15WRX_STI_US_EN.book 23 ペー   
DI-24
Rear Differential (T-type)
DIFFERENTIALS
9) Using the ST, remove the bearing cone.
NOTE:
Do not attempt to disassemble the parts unless
necessary.
Set the ST so that its claws catch the edge of the
bearing cone.
Never mix up the RH and LH bearing races and
cones.
ST 18759AA000 PULLER ASSY
10) Remove the hypoid driven gear by loosening
hypoid driven gear bolts.
11) Remove the pinion shaft lock pin from hypoid
driven gear side using ST.
ST 899904100 STRAIGHT PIN REMOVER
12) Draw out the pinion mate shaft, and remove
pinion mate gears, pinion mate gear washers, side
gears, and side gear thrust washers.
NOTE:
The gears and washers should be marked with RH
or LH, front or rear, or kept separately.
13) Remove the self-locking nut while securing the
companion flange with ST.
ST 498427200 FLANGE WRENCH
14) Extract the companion flange with a puller.
DI-00316
ST
DI-00068
DI-00701
ST
(A) Side gear
(B) Pinion mate gear
(C) Side gear thrust washer
(D) Differential case
(E) Pinion mate shaft
(F) Pinion mate gear washer
(A) Companion flange
(B) Puller
DI-00685
(E)
(D)
(F)
(F)
(B)
(A)
(C)
(A)
(C)
DI-00071
ST
DI-00142
(B)
(A)
15WRX_STI_US_EN.book 24 ペー   
DI-25
Rear Differential (T-type)
DIFFERENTIALS
15) Press the end of drive pinion shaft using ST
and remove the rear bearing cone, preload adjust-
ing spacer and washer.
NOTE:
Hold the drive pinion so as not to drop it.
ST 398467700 DRIFT
16) Remove the rear bearing cone from drive pin-
ion by supporting the cone with ST.
NOTE:
Place the replacer so that its center-recessed side
faces the bearing cone.
ST 398517700 REPLACER
17) Remove the front oil seal from differential carri-
er using ST.
ST 398527700 PULLER ASSY
18) Remove the pilot bearing together with the front
bearing cone and spacer using the ST.
ST 398467700 DRIFT
19) When replacing the bearings, use a brass bar
to tap out the front bearing race and rear bearing
race in this order to remove them.
(A) Differential carrier
(B) Front oil seal
DI-00073
ST
DI-00074
ST
DI-00145
(B)
(A)
(A) Pilot bearing
(B) Spacer
(C) Front bearing
(D) Rear bearing race
(A) 2 cutout portions along diagonal lines
(B) Tap alternately with brass bar.
DI-00076
ST
(B)
(A)
(C)
(D)
DI-00077
(B)
(A)
15WRX_STI_US_EN.book 25 ペー   
DI-26
Rear Differential (T-type)
DIFFERENTIALS
2. T-TYPE (H5)
To detect the real cause of trouble, inspect the fol-
lowing items before disassembling.
Tooth contact and backlash between hypoid
driven gear and drive pinion
Hypoid driven gear runout on its back surface
Total preload of drive pinion
1) Set the ST on vise and install the differential as-
sembly to ST.
ST 398217700 ATTACHMENT SET
2) Remove the drain plug and the oil temperature
sensor, and drain the gear oil.
NOTE:
Remove the oil temperature sensor and the adapt-
er as a unit.
3) Remove the air breather cap.
NOTE:
Do not attempt to remove the air breather cap
unless necessary.
Whenever the air breather cap is removed, re-
place it with a new part.
4) Remove the bolts, and then remove the rear
cover.
5) Remove the side retainer attachment bolts, set
the ST to differential case, and extract the side re-
tainers RH and LH with a puller.
NOTE:
Side retainer shim of each side should be kept
together with its mating retainer.
Keep the side retainers separate by attaching
tags or in similar ways to make it possible to identify
RH and LH sides during reassembly.
ST 398457700 ATTACHMENT
6) Pull out the differential case assembly from the
differential carrier.
NOTE:
Be careful not to hit the teeth of hypoid driven gear
against the differential carrier.
7) Remove the oil seal and O-ring from the side re-
tainer.
(A) Air breather cap
(B) Rear cover
(C) Oil temperature sensor
(D) Drain plug
DI-00061
ST
DI-01003
(A)
(D)
(C)
(B)
DI-00064
ST
DI-00065
15WRX_STI_US_EN.book 26 ペー   
DI-27
Rear Differential (T-type)
DIFFERENTIALS
8) When replacing the side bearing, remove the
bearing race from the side retainer using ST.
ST 398527700 PULLER ASSY
9) Using the ST, remove the bearing cone.
NOTE:
Do not attempt to disassemble the parts unless
necessary.
Set the puller so that its claws catch the edge of
the bearing cone.
Never mix up the RH and LH bearing races and
cones.
ST 18759AA000 PULLER ASSY
10) Remove the hypoid driven gear by loosening
hypoid driven gear bolts.
NOTE:
Do not disassemble the differential case assembly.
11) Remove the self-locking nut while securing the
companion flange with ST.
ST 18633AA000 WRENCH COMPL
12) Extract the companion flange with a puller.
13) Press the end of drive pinion shaft by using the
ST, and remove the drive pinion shaft, rear bearing
cone, preload adjusting spacer and washer.
NOTE:
Hold the drive pinion so as not to drop it.
ST 398467700 DRIFT
DI-00066
ST
DI-00316
ST
DI-00068
(A) Companion flange
(B) Puller
DI-00071
ST
DI-00142
(B)
(A)
DI-00073
ST
15WRX_STI_US_EN.book 27 ペー   
DI-28
Rear Differential (T-type)
DIFFERENTIALS
14) Remove the rear bearing cone from drive pin-
ion by supporting the cone with ST.
NOTE:
Place the replacer so that its center-recessed side
faces the bearing cone.
ST 398517700 REPLACER
15) Remove the front oil seal from differential carri-
er using ST.
ST 398527700 PULLER ASSY
16) Remove the pilot bearing together with the front
bearing cone and spacer using the ST.
ST 398467700 DRIFT
17) When replacing the bearings, use a brass bar
to tap out the front bearing race and rear bearing
race in this order to remove them.
(A) Differential carrier
(B) Front oil seal
DI-00074
ST
DI-00145
(B)
(A)
(A) Pilot bearing
(B) Spacer
(C) Front bearing
(D) Rear bearing race
(A) 2 cutout portions along diagonal lines
(B) Tap alternately with brass bar.
DI-00076
ST
(B)
(A)
(C)
(D)
DI-00077
(B)
(A)
15WRX_STI_US_EN.book 28 ペー   
DI-29
Rear Differential (T-type)
DIFFERENTIALS
D: ASSEMBLY
1. T-TYPE (B1, B2)
NOTE:
Assemble in the reverse order of disassembly.
Check and adjust each part during assembly.
Keep the shims and washers in order, so that
they are not improperly installed.
Thoroughly clean the surfaces on which the
shims, washers and bearings are to be installed.
Apply gear oil when installing the bearings and
thrust washers.
Be careful not to mix up the RH and LH bearing
races.
Use a new O-ring and gasket.
Replace the oil seal with a new part at every dis-
assembly.
Be careful not to mix up the rear differential side
oil seal RH and LH.
Apply differential gear oil to the lips when install-
ing the oil seal.
1) Adjusting preload for front and rear bearings
NOTE:
Adjust the bearing preload between front and rear
bearings with preload adjusting spacer and wash-
er. Pinion height adjusting washer is not affected by
this adjustment. The adjustment must not be car-
ried out with oil seal inserted.
(1) Install the rear bearing race into the differen-
tial carrier using ST1 and ST2.
ST1 398477701 HANDLE
ST2 398477703 DRIFT 2
(2) Install the front bearing race to the differen-
tial carrier using ST1 and ST2.
NOTE:
Use a new front bearing race.
ST1 398477701 HANDLE
ST2 398477702 DRIFT
(3) Insert ST1 into the differential carrier with
the pinion height adjusting washer and rear
bearing cone fitted onto it.
NOTE:
At this time, install a provisionally selected or
previously used pinion height adjusting washer.
Measure and record the thickness.
If tooth contact (drive pinion, hypoid driven gear)
is normal in the inspection before disassembling,
verify that the washer is not deformed, and then re-
use the used washer.
(4) Install the preload adjusting spacer and
washer, front bearing cone, ST2, companion
flange and self-locking nut.
NOTE:
Use new front bearing cone.
ST1 398507702 DUMMY SHAFT
ST2 398507703 DUMMY COLLAR
DI-00697
DI-00079
ST2
ST1
(A) Pinion height adjusting washer
(B) Preload adjusting spacer
(C) Preload adjusting washer
DI-00080
(B)
(A)
(C)
ST2
ST1
15WRX_STI_US_EN.book 29 ペー   
DI-30
Rear Differential (T-type)
DIFFERENTIALS
(5) Turn the ST1 by hand to smooth the bear-
ing, and tighten the self-locking nut while mea-
suring the initial load or initial torque with a
spring scale or torque wrench. Select the pre-
load adjusting washer and spacer so that the
specified preload is obtained when nut is tight-
ened to the specified torque.
NOTE:
Measure the preload in direction of tangent to the
flange.
Be careful not to give excessive preload.
When tightening the self-locking nut, lock ST1
with ST2 as shown in the figure.
ST1 398507702 DUMMY SHAFT
ST2 398507704 BLOCK
Tightening torque:
181.5 N·m (18.5 kgf-m, 133.9 ft-lb)
Initial load:
18.1 — 38.8 N (1.8 — 4.0 kgf, 4.1 — 8.7 lbf)
Initial torque:
0.69 — 1.47 N·m (0.07 — 0.15 kgf-m, 0.51 —
1.08 ft-lb)
DI-00081
ST1
ST2
DI-00117
Preload adjusting washer
Part No. Thickness mm (in)
383705200 2.59 (0.1020)
383715200 2.57 (0.1012)
383725200 2.55 (0.1004)
383735200 2.53 (0.0996)
383745200 2.51 (0.0988)
383755200 2.49 (0.0980)
383765200 2.47 (0.0972)
383775200 2.45 (0.0965)
383785200 2.43 (0.0957)
383795200 2.41 (0.0949)
383805200 2.39 (0.0941)
383815200 2.37 (0.0933)
383825200 2.35 (0.0925)
383835200 2.33 (0.0917)
383845200 2.31 (0.0909)
Preload adjusting spacer
Part No. Length mm (in)
383695201 56.2 (2.213)
383695202 56.4 (2.220)
383695203 56.6 (2.228)
383695204 56.8 (2.236)
383695205 57.0 (2.244)
383695206 57.2 (2.252)
DI-00481
15WRX_STI_US_EN.book 30 ペー   
DI-31
Rear Differential (T-type)
DIFFERENTIALS
2) Adjusting drive pinion height:
Adjust the drive pinion height with pinion height ad-
justing washer installed between the rear bearing
cone and the back of pinion gear.
(1) Attach the ST2.
ST1 398507702 DUMMY SHAFT
ST2 398507701 DIFFERENTIAL CARRIER
GAUGE
ST3 398507703 DUMMY COLLAR
(2) Measure the clearance “N” between the end
of ST2 and the end surface of ST1 by using a
thickness gauge.
NOTE:
Make sure there is no clearance between the differ-
ential carrier and ST2.
ST1 398507702 DUMMY SHAFT
ST2 398507701 DIFFERENTIAL CARRIER
GAUGE
(3) Obtain the thickness of pinion height adjust-
ing washer to be inserted from the following for-
mula, and replace the temporarily installed
washer with this one.
T = To + N – (H × 0.01) – 0.20 mm (0.0079 in)
(Example of calculation)
To = 3.39 mm (0.1335 in)
N = 0.24 mm (0.0094 in)
H = + 1
T = 3.39 mm (0.1335 in) + 0.24 mm (0.0094 in)
– 0.01 mm (0.0004 in) – 0.20 mm (0.0079 in) =
3.42 mm (0.1346 in)
Result: Thickness = 3.42 mm (0.1346 in)
Therefore use washer 383605200.
(A) Pinion height adjusting washer
DI-00083
RH
LH
N
(A)
ST2ST3 ST1
DI-00084
ST2
ST1
T
Thickness of pinion height adjusting
washer mm (in)
To
Thickness of washer temporarily
inserted mm (in)
N Clearance of thickness gauge mm (in)
H Figure marked on drive pinion head
Memo:
Pinion height adjusting washer
Part No. Thickness mm (in)
383495200 3.09 (0.1217)
383505200 3.12 (0.1228)
383515200 3.15 (0.1240)
383525200 3.18 (0.1252)
383535200 3.21 (0.1264)
383545200 3.24 (0.1276)
383555200 3.27 (0.1287)
383565200 3.30 (0.1299)
383575200 3.33 (0.1311)
383585200 3.36 (0.1323)
383595200 3.39 (0.1335)
383605200 3.42 (0.1346)
383615200 3.45 (0.1358)
383625200 3.48 (0.1370)
383635200 3.51 (0.1382)
383645200 3.54 (0.1394)
383655200 3.57 (0.1406)
383665200 3.60 (0.1417)
383675200 3.63 (0.1429)
383685200 3.66 (0.1441)
15WRX_STI_US_EN.book 31 ペー   
DI-32
Rear Differential (T-type)
DIFFERENTIALS
3) Install the selected pinion height adjusting wash-
er on drive pinion, and press the rear bearing cone
into position with ST.
ST 398177700 INSTALLER
4) Insert the drive pinion into the differential carrier,
and install the preselected preload adjusting spac-
er and washer.
5) Press-fit the front bearing cone with ST1, ST2
and ST3.
ST1 398507703 DUMMY COLLAR
ST2 399780104 WEIGHT
ST3 899580100 INSTALLER
6) Insert the spacer, then press-fit the pilot bearing
with ST1 and ST2.
NOTE:
Use a new pilot bearing.
ST1 399780104 WEIGHT
ST2 899580100 INSTALLER
7) Using the ST, install the oil seal.
NOTE:
Use a new oil seal.
Press-fit until the oil seal end comes 1 mm (0.04
in) inward from end of carrier.
Apply differential gear oil to the oil seal lips.
ST 498447120 INSTALLER
8) Press-fit the companion flange with ST1 and
ST2.
NOTE:
Be careful not to damage the bearing.
ST1 899874100 INSTALLER
ST2 399780104 WEIGHT
(A) Drive pinion
(B) Preload adjusting spacer
(C) Preload adjusting washer
(D) Differential carrier
DI-00085
ST
DI-00704
(A)
(B)
(C)
(D)
DI-00087
ST3
ST1
ST2
DI-00088
ST2
ST1
DI-00089
ST
DI-00090
ST1
ST2
15WRX_STI_US_EN.book 32 ペー   
DI-33
Rear Differential (T-type)
DIFFERENTIALS
9) Apply seal material on the drive pinion shaft
thread and new self-locking nut seat.
Seal material:
THREE BOND 1324 (Part No. 004403042) or
equivalent
10) Attach the new self-locking nut and use the ST
to fix the companion flange in place, then tighten
the self-locking nut.
Tightening torque:
181.5 N·m (18.5 kgf-m, 133.9 ft-lb)
ST 498427200 FLANGE WRENCH
11) Check the initial torque or initial load.
Initial load:
18.1 — 38.8 N (1.8 — 4.0 kgf, 4.1 — 8.7 lbf)
Initial torque:
0.69 — 1.47 N·m (0.07 — 0.15 kgf-m, 0.51 —
1.08 ft-lb)
12) Assembling differential case
(1) Install the side gears and pinion mate gears,
with their side gear thrust washers, pinion mate
gear washer, and pinion mate shaft, into the dif-
ferential case.
NOTE:
Apply gear oil on both sides of the washer and on
the pinion mate shaft before installing.
Insert the pinion mate shaft into the differential
case by aligning the pin holes.
(2) Measure the side gear backlash.
Side gear backlash:
0.10 — 0.20 mm (0.004 — 0.008 in)
(3) Adjust the backlash as specified by select-
ing side gear thrust washer.
DI-00091
ST
DI-00117
DI-00481
Side gear thrust washer
Part No. Thickness mm (in)
383445201 0.75 — 0.80 (0.0295 — 0.0315)
383445202 0.80 — 0.85 (0.0315 — 0.0335)
383445203 0.85 — 0.90 (0.0335 — 0.0354)
DI-00686
DI-00240
15WRX_STI_US_EN.book 33 ペー   
DI-34
Rear Differential (T-type)
DIFFERENTIALS
(4) Check the condition of rotation after apply-
ing oil to the gear tooth surfaces and washer
surfaces.
(5) Drive the pinion shaft lock pin into the differ-
ential case.
NOTE:
Use a new pinion shaft lock pin.
ST 899904100 STRAIGHT PIN REMOVER
13) Install the driven gear to the differential case.
NOTE:
Before installing bolts, apply seal material to bolt
threads.
Seal material:
THREE BOND 1324 (Part No. 004403042) or
equivalent
Make sure there is no clearance between the dif-
ferential case and driven gear.
Tighten opposing bolts in order.
Tightening torque:
103 N·m (10.5 kgf-m, 76.0 ft-lb)
14) Using the ST, press-fit the side bearing to the
differential case.
ST 398487700 DRIFT
15) Using the ST, press-fit the side bearing outer
race to the side retainer.
CAUTION:
Make sure that the bearing outer races and
cones are properly assembled.
ST 398417700 DRIFT
16) Side retainer shim adjustment
(1) The hypoid driven gear backlash and side
bearing preload can be adjusted by the side re-
tainer shim thickness.
(2) Install the differential case assembly into dif-
ferential carrier in the reverse order of disas-
sembly.
NOTE:
Be careful not to hit the teeth of hypoid driven gear
against the differential carrier.
(3) Install the side retainer shim.
NOTE:
Be careful not to mix up the side retainer shim
RH and LH.
Replace broken or corroded side retainer shims
with a new part of the same thickness.
DI-00068
DI-00095
ST
Side retainer shim
Part No. Thickness mm (in)
383475201 0.20 (0.0079)
383475202 0.25 (0.0098)
383475203 0.30 (0.0118)
383475204 0.40 (0.0157)
383475205 0.50 (0.0197)
DI-00324
ST
DI-00065
15WRX_STI_US_EN.book 34 ペー   
DI-35
Rear Differential (T-type)
DIFFERENTIALS
(4) Align the arrow mark on the differential car-
rier with the arrow mark on the side retainer
when installing the side retainer.
NOTE:
Be careful that the side bearing outer race is not
damaged by the bearing roller.
(5) Tighten the side retainer bolts.
Tightening torque:
10.5 N·m (1.1 kgf-m, 7.7 ft-lb)
(6) Measure the hypoid driven gear to drive pin-
ion backlash. Set the magnet base on differen-
tial carrier. Align the contact point of dial gauge
with tooth face of hypoid driven gear, and move
hypoid driven gear while holding drive pinion
still. Read the value indicated on dial gauge. If
the backlash is outside the standard range, ad-
just the side retainer shim by the following
method.
• When backlash is less than 0.1 mm (0.004
in):
Reduce the thickness of shim on the back side
of the hypoid driven gear and increase the
thickness of shims on the teeth side of the hy-
poid driven gear.
• When backlash exceeds 0.2 mm (0.008 in):
Increase the thickness of shim on the back side
of the hypoid driven gear and reduce the thick-
ness of shims on the teeth side of the hypoid
driven gear.
Backlash:
0.10 — 0.20 mm (0.004 — 0.008 in)
(7) Measure the total preload of the drive pin-
ion. If the total preload is outside the specifica-
tion range, adjust the thickness of side retainer
shims, increasing/reducing both shims by an
even amount at a time.
Total preload:
20.7 — 54.4 N (2.1 — 5.5 kgf, 4.7 — 12.2 lbf)
(A) Arrow mark (on the side retainer)
(B) Arrow mark (on the differential carrier)
DI-00543
(B)
(A)
DI-00487
DI-00099
15WRX_STI_US_EN.book 35 ペー   
DI-36
Rear Differential (T-type)
DIFFERENTIALS
17) Recheck the hypoid driven gear to drive pinion
backlash.
Backlash:
0.10 — 0.20 mm (0.004 — 0.008 in)
18) Check pinion and hypoid driven gears rotate
smoothly and make sure of the hypoid driven gear
runout on its back surface. If the hypoid driven gear
runout on its back surface exceeds the specifica-
tion, check for any foreign objects between the hy-
poid driven gear and differential case, and for any
deformation of the differential case or hypoid driven
gear.
Hypoid driven gear back surface runout:
0.05 mm (0.002 in)
19) Check and adjustment of the tooth contact of
hypoid driven gear and drive pinion
(1) Apply lead-free red dye evenly on the both
sides of three to four teeth of the hypoid driven
gear. Check the contact pattern after rotating
the hypoid driven gear several revolutions back
and forth until a definite contact pattern appears
on the hypoid driven gear.
(2) When the contact pattern is not correct, re-
adjust.
NOTE:
Be sure to wipe off the lead-free red dye completely
after the adjustment is completed.
Correct tooth contact
Check item: Tooth contact pattern is slightly
shifted toward toe side under no-load rota-
tion. (When driving, it moves towards the
heel side.)
DI-00099
DI-00101
(A) Toe side
(B) Heel side
(A)
(B)
MT-01401
15WRX_STI_US_EN.book 36 ペー   
DI-37
Rear Differential (T-type)
DIFFERENTIALS
Face contact
Check item: Backlash is too large.
Contact pattern
Corrective action: Increase thickness of pinion
height adjusting washer according to the proce-
dure for bringing drive pinion close to hypoid
driven gear side.
Flank contact
Check item: Backlash is too small.
Contact pattern
Corrective action: Reduce the thickness of pin-
ion height adjusting washer according to the
procedure for bringing drive pinion away from
hypoid driven gear.
AT-00208
AT-00212
AT-00209
AT-00213
15WRX_STI_US_EN.book 37 ペー   
DI-38
Rear Differential (T-type)
DIFFERENTIALS
Toe contact (inside contact)
Check item: Teeth contact area is too small.
Contact pattern
Corrective action: Reduce the thickness of pin-
ion height adjusting washer according to the
procedure for bringing drive pinion away from
hypoid driven gear.
Heel contact (outside end contact)
Check item: Teeth contact area is too small.
Contact pattern
Corrective action: Increase thickness of pinion
height adjusting washer according to the proce-
dure for bringing drive pinion close to hypoid
driven gear side.
AT-00210
AT-00213
AT-00211
AT-00212
15WRX_STI_US_EN.book 38 ペー   
DI-39
Rear Differential (T-type)
DIFFERENTIALS
20) If proper tooth contact is not obtained, readjust
the drive pinion height by changing the RH and LH
side retainer shims and the hypoid gear backlash.
(1) Drive pinion height
ST1 398507702 DUMMY SHAFT
ST2 398507701 DIFFERENTIAL CARRIER
GAUGE
T = To + N – (H × 0.01) – 0.20 mm (0.0079 in)
(2) Hypoid gear backlash
Backlash:
0.10 — 0.20 mm (0.004 — 0.008 in)
21) Remove the RH and LH side retainers.
22) Install the O-ring to left and right side retainers.
NOTE:
Use new O-rings.
23) Install the oil seal to the side retainers on both
sides. <Ref. to DI-55, REPLACEMENT, Rear Dif-
ferential Side Oil Seal.>
24) Align the arrow mark on the differential carrier
with the arrow mark on the side retainer when in-
stalling the side retainer.
25) Apply liquid gasket to the bolts indicated by ar-
rows, and tighten the bolts.
Liquid gasket:
THREE BOND 1110F, THREE BOND 1110B or
equivalent
Tightening torque:
10.5 N·m (1.1 kgf-m, 7.7 ft-lb)
26) Install the gasket and rear cover, and tighten
the bolts to specified torque.
NOTE:
Use a new gasket.
Tightening torque:
29.5 N·m (3.0 kgf-m, 21.8 ft-lb)
T
Thickness of pinion height adjusting
washer mm (in)
To
Thickness of washer temporarily
inserted mm (in)
N Clearance of thickness gauge mm (in)
H Figure marked on drive pinion head
Memo:
DI-00084
ST2
ST1
DI-00099
(A) Arrow mark (on the side retainer)
(B) Arrow mark (on the differential carrier)
DI-00543
(B)
(A)
DI-00461
DI-00490
15WRX_STI_US_EN.book 39 ペー   
DI-40
Rear Differential (T-type)
DIFFERENTIALS
27) Install the air breather cap.
NOTE:
When installing the air breather cap, do not tap sec-
tion (A). Be sure to tap section (B) to install.
28) Install the drain plug.
NOTE:
Apply liquid gasket to the drain plug.
Liquid gasket:
THREE BOND 1105 (Part No. 004403010) or
equivalent
Tightening torque:
49 N·m (5.0 kgf-m, 36.1 ft-lb)
29) Install the filler plug.
NOTE:
After installing the rear differential assembly to the
vehicle, fill the gear oil, then apply liquid gasket,
and tighten to the specified torque. <Ref. to DI-16,
REPLACEMENT, Differential Gear Oil.>
2. T-TYPE (H5)
NOTE:
Assemble in the reverse order of disassembly.
Check and adjust each part during assembly.
Keep the shims and washers in order, so that
they are not improperly installed.
Thoroughly clean the surfaces on which the
shims, washers and bearings are to be installed.
Apply gear oil when installing the bearings and
thrust washers.
Be careful not to mix up the RH and LH bearing
races.
Use a new O-ring and gasket.
Replace the oil seal with a new part at every dis-
assembly.
Be careful not to mix up the oil seal RH and LH.
Apply differential gear oil to the lips when install-
ing the oil seal.
1) Adjusting preload for front and rear bearings
NOTE:
Adjust the bearing preload between front and rear
bearings with spacer and washer. Pinion height ad-
justing washer is not affected by this adjustment.
The adjustment must not be carried out with oil seal
inserted.
2) Using the ST, press-fit the rear bearing race to
the differential carrier.
ST 398417700 DRIFT
DI-00674
(A)
(B)
DI-00697
ST
DI-00318
15WRX_STI_US_EN.book 40 ペー   
DI-41
Rear Differential (T-type)
DIFFERENTIALS
3) Using the ST, press-fit the front bearing race to
the differential carrier.
NOTE:
Use a new front bearing race.
ST 398477702 DRIFT
4) Selecting the pinion height adjusting washer
(1) Measure the thickness of the inserted pinion
height adjusting washer.
(2) Read the markings on both the current drive
pinion gear and the new pinion gear.
NOTE:
No marking means 0 (zero).
(3) Calculate the thickness of pinion height ad-
justing washer to be inserted from the following
formula, and replace the installed washer with a
new washer of the calculated thickness.
T = T1 + (T2 × 0.01 – T3 × 0.01)
(Example of calculation)
T1 = 3.30 mm (0.1299 in), T2 = +2, T3 = –1
T = 3.30 mm (0.1299 in) + {(2 × 0.01) – (–1 ×
0.01)} = 3.33 mm (0.1311 in)
Result: Thickness = 3.33 mm (0.1311 in)
The washer with part number 38336AA310 is
used.
DI-00319
0
0
5
5
10
10
15
DI-00320
+2
DI-00321
T
Thickness of selected pinion height adjusting
washer mm (in)
T1
Thickness of inserted pinion height adjusting
washer mm (in)
T2
Number of the installed drive pinion gear mark-
ing mm (in)
T3
Number of new drive pinion gear marking mm
(in)
Memo:
Pinion height adjusting washer
Part No. Thickness mm (in)
38336AA230 3.09 (0.1217)
38336AA240 3.12 (0.1228)
38336AA250 3.15 (0.1240)
38336AA260 3.18 (0.1252)
38336AA270 3.21 (0.1264)
38336AA280 3.24 (0.1276)
38336AA290 3.27 (0.1287)
38336AA300 3.30 (0.1299)
38336AA310 3.33 (0.1311)
38336AA320 3.36 (0.1323)
38336AA330 3.39 (0.1335)
38336AA340 3.42 (0.1346)
38336AA350 3.45 (0.1358)
38336AA360 3.48 (0.1370)
38336AA370 3.51 (0.1382)
38336AA380 3.54 (0.1394)
38336AA390 3.57 (0.1406)
38336AA400 3.60 (0.1417)
38336AA410 3.63 (0.1429)
38336AA420 3.66 (0.1441)
15WRX_STI_US_EN.book 41 ペー   
DI-42
Rear Differential (T-type)
DIFFERENTIALS
5) Install the selected pinion height adjusting wash-
er on drive pinion, and push the rear bearing cone
into position with ST.
ST 18674AA000 INSTALLER
6) Insert the drive pinion into the differential carrier,
and install the originally attached preload adjusting
spacer and washer.
7) Install the front bearing cone.
NOTE:
Use new front bearing cone.
8) Insert the spacer and press-fit the pilot bearing
using ST.
NOTE:
Use a new pilot bearing.
ST1 399780104 WEIGHT
ST2 899580100 INSTALLER
ST3 398507703 DUMMY COLLAR
ST4 498937110 HOLDER DRIVE PINION
9) Press-fit the companion flange with ST1, ST2,
and ST3.
NOTE:
Be careful not to damage the bearing.
ST1 899874100 INSTALLER
ST2 399780104 WEIGHT
ST3 498937110 HOLDER DRIVE PINION
10) Attach the self-locking nut and use the ST to fix
the companion flange in place, then tighten the
self-locking nut.
Tightening torque:
181.5 N·m (18.5 kgf-m, 133.9 ft-lb)
ST 18633AA000 WRENCH COMPL
(A) Drive pinion
(B) Preload adjusting spacer
(C) Preload adjusting washer
(D) Differential carrier
DI-00085
ST
DI-00704
(A)
(B)
(C)
(D)
ST2
ST3
ST1
ST4
ST1
ST4
DI-00322
ST3
ST1
ST2
ST2
DI-00323
DI-00091
ST
15WRX_STI_US_EN.book 42 ペー   
DI-43
Rear Differential (T-type)
DIFFERENTIALS
11) Rotate the drive pinion shaft 10 times or more
to fit it in the respective taper roller bearing, and
then measure the initial load or initial torque.
Initial load:
24.1 — 38.6 N (2.5 — 3.9 kgf, 5.4 — 8.7 lbf)
Initial torque:
0.98 — 1.57 N·m (0.10 — 0.16 kgf-m, 0.72 —
1.16 ft-lb)
12) When the bearing preload is out of the speci-
fied range, select the preload adjusting washer and
spacer from the following table in order to make it
within the specified range.
13) Remove the self-locking nut while securing the
companion flange with ST.
ST 18633AA000 WRENCH COMPL
DI-00715
DI-00481
Preload adjusting washer
Part No. Thickness mm (in)
383705200 2.59 (0.1020)
383715200 2.57 (0.1012)
383725200 2.55 (0.1004)
383735200 2.53 (0.0996)
383745200 2.51 (0.0988)
383755200 2.49 (0.0980)
383765200 2.47 (0.0972)
383775200 2.45 (0.0965)
383785200 2.43 (0.0957)
383795200 2.41 (0.0949)
383805200 2.39 (0.0941)
383815200 2.37 (0.0933)
383825200 2.35 (0.0925)
383835200 2.33 (0.0917)
383845200 2.31 (0.0909)
Preload adjusting spacer
Part No. Length mm (in)
31454AA130 52.2 (2.055)
31454AA140 52.4 (2.063)
31454AA150 52.6 (2.071)
31454AA160 52.8 (2.079)
31454AA170 53.0 (2.087)
31454AA180 53.2 (2.094)
DI-00091
ST
15WRX_STI_US_EN.book 43 ペー   
DI-44
Rear Differential (T-type)
DIFFERENTIALS
14) Extract the companion flange with a puller.
15) Using the ST, install the oil seal.
NOTE:
Use a new oil seal.
Press-fit until the oil seal end comes 1 mm (0.04
in) inward from end of carrier.
Apply differential gear oil to the oil seal lips.
ST 498447120 INSTALLER
16) Press-fit the companion flange with ST1, ST2,
and ST3.
ST1 899874100 INSTALLER
ST2 399780104 WEIGHT
ST3 498937110 HOLDER DRIVE PINION
NOTE:
Be careful not to damage the bearing.
17) Apply seal material on the drive pinion shaft
thread and new self-locking nut seat.
Seal material:
THREE BOND 1324 (Part No. 004403042) or
equivalent
18) Attach the new self-locking nut and use the ST
to fix the companion flange in place, then tighten
the self-locking nut.
Tightening torque:
181.5 N·m (18.5 kgf-m, 133.9 ft-lb)
ST 18633AA000 WRENCH COMPL
19) Check the initial torque or initial load.
Initial load:
24.1 — 38.6 N (2.5 — 3.9 kgf, 5.4 — 8.7 lbf)
Initial torque:
0.98 — 1.57 N·m (0.10 — 0.16 kgf-m, 0.72 —
1.16 ft-lb)
(A) Companion flange
(B) Puller
DI-00142
(B)
(A)
DI-00089
ST
ST3
ST1
ST2
ST2
DI-00323
DI-00071
ST
DI-00715
DI-00481
15WRX_STI_US_EN.book 44 ペー   
DI-45
Rear Differential (T-type)
DIFFERENTIALS
20) Install the driven gear to the differential case.
NOTE:
Before installing bolts, apply seal material to bolt
threads.
Seal material:
THREE BOND 1324 (Part No. 004403042) or
equivalent
Make sure there is no clearance between the dif-
ferential case and driven gear.
Tighten opposing bolts in order.
Tightening torque:
103 N·m (10.5 kgf-m, 76.0 ft-lb)
21) Using the ST, press-fit the side bearing to the
differential case.
ST 398487700 DRIFT
22) Using the ST, press-fit the side bearing outer
race to the side retainer.
CAUTION:
Make sure that the bearing outer races and
cones are properly assembled.
ST 398417700 DRIFT
23) Side retainer shim adjustment
(1) The hypoid driven gear backlash and side
bearing preload can be adjusted by the side re-
tainer shim thickness.
(2) Install the differential case assembly into dif-
ferential carrier in the reverse order of disas-
sembly.
NOTE:
Be careful not to hit the teeth of hypoid driven gear
against the differential carrier.
(3) Install the side retainer shim.
NOTE:
Be careful not to mix up the side retainer shim
RH and LH.
Replace broken or corroded side retainer shims
with a new part of the same thickness.
(4) During installation, align the arrow mark on
the differential carrier with the arrow mark on the
side retainer when installing the side retainer.
NOTE:
Be careful that side bearing outer race is not dam-
aged by the bearing roller.
DI-00068
DI-00095
ST
DI-00324
ST
Side retainer shim
Part No. Thickness mm (in)
383475201 0.20 (0.0079)
383475202 0.25 (0.0098)
383475203 0.30 (0.0118)
383475204 0.40 (0.0157)
383475205 0.50 (0.0197)
(A) Arrow mark (on the side retainer)
(B) Arrow mark (on the differential carrier)
DI-00065
DI-00543
(B)
(A)
15WRX_STI_US_EN.book 45 ペー   
DI-46
Rear Differential (T-type)
DIFFERENTIALS
(5) Tighten the side retainer bolts.
Tightening torque:
10.5 N·m (1.1 kgf-m, 7.7 ft-lb)
(6) Measure the hypoid driven gear to drive pin-
ion backlash. Set the magnet base on differen-
tial carrier. Align the contact point of dial gauge
with tooth face of hypoid driven gear, and move
hypoid driven gear while holding drive pinion
still. Read the value indicated on dial gauge. If
the backlash is outside the standard range, ad-
just the side retainer shim by the following
method.
When backlash is less than 0.1 mm (0.004
in):
Reduce the thickness of shim on the back side
of the hypoid driven gear and increase the
thickness of shims on the teeth side of the hy-
poid driven gear.
When backlash exceeds 0.2 mm (0.008
in):
Increase the thickness of shim on the back side
of the hypoid driven gear and reduce the thick-
ness of shims on the teeth side of the hypoid
driven gear.
Backlash:
0.10 — 0.20 mm (0.004 — 0.008 in)
(7) Measure the total preload of the drive pin-
ion. If the total preload is not within specifica-
tion, adjust the thickness of side retainer shims,
increasing/reducing both shims by an even
amount on both sides.
Total preload:
26.5 — 53 N (2.7 — 5.4 kgf, 6.0 — 11.9 lbf)
24) Recheck the hypoid driven gear to drive pinion
backlash.
Backlash:
0.10 — 0.20 mm (0.004 — 0.008 in)
25) Check drive pinion and hypoid driven gears ro-
tate smoothly and make sure of the hypoid driven
gear runout on its back surface. If the runout on the
back side of the hypoid driven gear exceeds the
specification, check for any foreign material be-
tween the hypoid driven gear and differential case,
and for any deformation of the case or gear.
Hypoid driven gear back surface runout:
0.05 mm (0.002 in)
DI-00487
DI-00099
DI-00099
DI-00101
15WRX_STI_US_EN.book 46 ペー   
DI-47
Rear Differential (T-type)
DIFFERENTIALS
26) Checking and adjusting the tooth contact of hy-
poid driven gear
(1) Apply lead-free red dye evenly on the both
sides of three to four teeth of the hypoid driven
gear. Check the contact pattern after rotating
the hypoid driven gear several revolutions back
and forth until a definite contact pattern appears
on the hypoid driven gear.
(2) When the contact pattern is not correct, re-
adjust.
NOTE:
Be sure to wipe off the lead-free red dye completely
after the adjustment is completed.
Correct tooth contact
Check item: Tooth contact pattern is slightly
shifted toward toe side under no-load rota-
tion. (When driving, it moves towards the
heel side.)
Face contact
Check item: Backlash is too large.
Contact pattern
Corrective action: Increase thickness of pinion
height adjusting washer according to the proce-
dure for bringing drive pinion close to hypoid
driven gear side.
(A) Toe side
(B) Heel side
(A)
(B)
MT-01401
AT-00208
AT-00212
15WRX_STI_US_EN.book 47 ペー   
DI-48
Rear Differential (T-type)
DIFFERENTIALS
Flank contact
Check item: Backlash is too small.
Contact pattern
Corrective action: Reduce the thickness of pin-
ion height adjusting washer according to the
procedure for bringing drive pinion away from
hypoid driven gear.
Toe contact (inside contact)
Check item: Teeth contact area is too small.
Contact pattern
Corrective action: Reduce the thickness of pin-
ion height adjusting washer according to the
procedure for bringing drive pinion away from
hypoid driven gear.
AT-00209
AT-00213
AT-00210
AT-00213
15WRX_STI_US_EN.book 48 ペー   
DI-49
Rear Differential (T-type)
DIFFERENTIALS
Heel contact (outside end contact)
Check item: Teeth contact area is too small.
Contact pattern
Corrective action: Increase thickness of pinion
height adjusting washer according to the proce-
dure for bringing drive pinion close to hypoid
driven gear side.
27) If proper tooth contact is not obtained, readjust
the drive pinion height by changing the RH and LH
side retainer shims and the hypoid gear backlash.
28) Remove the RH and LH side retainers.
29) Install the O-ring to left and right side retainers.
NOTE:
Use new O-rings.
30) Install the oil seal to the side retainers on both
sides. <Ref. to DI-55, REPLACEMENT, Rear Dif-
ferential Side Oil Seal.>
31) Align the arrow mark on the differential carrier
with the arrow mark on the side retainer during in-
stallation.
32) Apply liquid gasket to the bolts indicated by ar-
rows, and tighten the side retainer bolt.
Liquid gasket:
THREE BOND 1110F (Part No. K0879Y0021),
THREE BOND 1110B or equivalent
Tightening torque:
10.5 N·m (1.1 kgf-m, 7.7 ft-lb)
33) Install the gasket and rear cover, and tighten
the bolts to specified torque.
NOTE:
Use a new gasket.
Tightening torque:
44 N·m (4.5 kgf-m, 32.5 ft-lb)
34) Install the air breather cap.
NOTE:
When installing the air breather cap, do not tap sec-
tion (A). Be sure to tap section (B) to install.
(A) Arrow mark (on the side retainer)
(B) Arrow mark (on the differential carrier)
AT-00211
AT-00212
DI-00543
(B)
(A)
DI-00461
DI-01004
(A)
(B)
15WRX_STI_US_EN.book 49 ペー   
DI-50
Rear Differential (T-type)
DIFFERENTIALS
35) Install the drain plug.
NOTE:
Use a new gasket.
Tightening torque:
60 N·m (6.1 kg-m, 44.3 ft-lb)
36) Install the oil temperature sensor.
NOTE:
Install the oil temperature sensor and the adapt-
er as a unit.
After installing the rear differential assembly to
the vehicle, fill the gear oil, then use a new gasket,
and tighten to the specified torque. <Ref. to DI-16,
REPLACEMENT, Differential Gear Oil.>
E: INSPECTION
Wash all the disassembled parts clean, and exam-
ine them for wear, damage and other defects. Re-
pair or replace the defective parts as necessary.
1) Hypoid driven gear and drive pinion
If there is evidently an abnormal tooth contact,
find out the cause and adjust until the teeth contact
correctly. Replace the gear if there is an excessive
worn or an incapable adjustment.
If crack, cutout or seizure is found, replace the
parts as a set. Slight damage of some teeth can be
corrected by oil stone or the like.
2) Side gear and pinion mate gear (T-type (B1, B2))
Replace if cracks, scoring or other defects are
evident on the tooth surface.
Replace if thrust washer contact surface is worn
or scored. Slight damages of the surface can be
corrected by oil stones or equivalent.
3) Bearing
Replace if seizure, peeling, wear, rust, dragging
during rotation, noise or other defect is evident.
4) Thrust washer of side gear and pinion mate gear
(T-type (B1, B2))
Replace if seized, flawed, abnormally worn or hav-
ing other defects.
5) Oil seal
Replace if deformed or damaged, and at every dis-
assembling.
6) Differential carrier
Replace if the bearing bores are worn or damaged.
7) Differential case
Replace if sliding surfaces are abnormally worn,
burned, or cracked.
8) Companion flange
Replace if the oil seal lip contact surface shows
cracking.
9) Rear differential oil temperature sensor (T-type
(H5))
(1) Check that the rear differential oil tempera-
ture sensor has no deformation, cracks or other
damages.
(2) Immerse the rear differential oil temperature
sensor and a thermometer in water.
CAUTION:
Take care not to allow water to get into the rear
differential oil temperature sensor connector. If
water gets into the connector, completely re-
move any water inside.
(A) Thermometer
(B) Rear differential oil temperature sensor
(C) Hexagonal part height: To approx.
2
/
3
DI-01005
(A)
(B)
(C)
15WRX_STI_US_EN.book 50 ペー   
DI-51
Rear Differential (T-type)
DIFFERENTIALS
(3) Raise water temperature gradually, mea-
sure the resistance between the rear differential
oil temperature sensor terminals when the tem-
perature is 20°C (68°F) and 80°C (176°F).
NOTE:
Stir the water to make the temperature of the wa-
ter as uniform as possible.
Take the resistance value only after it becomes
steady.
After inspection, wipe off the water completely.
1. SIDE GEAR BACKLASH (T-TYPE (B1,
B2))
Using a dial gauge, check the backlash of side
gear.
Side gear backlash:
0.10 — 0.20 mm (0.004 — 0.008 in)
If the side gear backlash is not within the specifica-
tion, select the side gear thrust washer and adjust
the side gear backlash as specified.
2. HYPOID DRIVEN GEAR BACKLASH
Using a dial gauge, check the backlash of hypoid
driven gear.
Hypoid driven gear backlash:
0.10 — 0.20 mm (0.004 — 0.008 in)
If the hypoid driven gear backlash is outside the
specification range, adjust the side bearing preload
and repair if necessary.
3. HYPOID DRIVEN GEAR RUNOUT ON ITS
BACK SURFACE
Using a dial gauge, check the hypoid driven gear
back surface runout.
Hypoid driven gear back surface runout:
0.05 mm (0.002 in)
If the hypoid driven gear runout on its back surface
exceeds the limit, replace the hypoid driven gear.
4. TOOTH CONTACT BETWEEN HYPOID
DRIVEN GEAR AND DRIVE PINION
Inspect the tooth contact between the hypoid driv-
en gear and drive pinion. <Ref. to DI-29, ASSEM-
BLY, Rear Differential (T-type).>
Water temperature Terminal No. Standard
20°C (68°F)
1 and 2
2.233 — 2.701 [kΩ]
80°C (176°F) 0.3122 — 0.3385 [kΩ]
12
DI-00980
DI-00315
DI-00099
DI-00101
15WRX_STI_US_EN.book 51 ペー   
DI-52
Rear Differential (T-type)
DIFFERENTIALS
5. TOTAL PRELOAD
Using a spring scale, check the total preload.
Total preload:
T-type (B1, B2):
20.7 — 54.4 N (2.1 — 5.5 kgf, 4.7 — 12.2 lbf)
T-type (H5):
26.5 — 53 N (2.7 — 5.4 kgf, 6.0 — 11.9 lbf)
If the total preload is not within the specification,
adjust the side retainer shim.
6. COMPANION FLANGE
1) If rust or dirt is attached to the companion flange,
remove them.
2) Set a dial gauge at a companion flange surface
(mating surface of propeller shaft and companion
flange), and then measure the companion flange
runout.
Limit of runout:
0.08 mm (0.003 in)
3) Set the gauge inside of the companion flange,
and measure the runout.
Limit of runout:
0.08 mm (0.003 in)
4) If either runout exceeds the limit, move the
phase of companion flange and drive pinion 90°
each, and find the point where the runout is within
the limit.
5) If the runout exceeds the limit after changing the
phase, replace the companion flange and recheck
the runout.
6) If the runout exceeds the limit after replacing the
companion flange, the drive pinion may be assem-
bled incorrectly or bearing is faulty.
F: ADJUSTMENT
1. SIDE GEAR BACKLASH (T-TYPE (B1,
B2))
Adjust the side gear backlash. <Ref. to DI-29, AS-
SEMBLY, Rear Differential (T-type).>
2. HYPOID DRIVEN GEAR BACKLASH
Adjust hypoid driven gear backlash. <Ref. to DI-29,
ASSEMBLY, Rear Differential (T-type).>
3. TOOTH CONTACT BETWEEN HYPOID
DRIVEN GEAR AND DRIVE PINION
Adjust the tooth contact between hypoid driven
gear and drive pinion gear. <Ref. to DI-29, ASSEM-
BLY, Rear Differential (T-type).>
4. TOTAL PRELOAD
Adjust the side retainer shim. <Ref. to DI-29, AS-
SEMBLY, Rear Differential (T-type).>
DI-00117
DI-00360
DI-00361
15WRX_STI_US_EN.book 52 ペー